Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Typekit is an online service which offers a subscription library of fonts.